The cutaneous manifestations of dermatomyositis (Chap. 388) are often distinctive, but, at times, they may resemble those of systemic lupus erythematosus (SLE) (Chap. 319), scleroderma (Chap. 323), or other overlapping connective tissue diseases (Chap. 323). The extent and severity of cutaneous disease may or may not correlate with the extent and severity of the myositis. The cutaneous manifestations of dermatomyositis are similar, whether the disease appears in children or the elderly, except that calcification of subcutaneous tissue is a common late sequela in childhood dermatomyositis.
The cutaneous signs of dermatomyositis may precede or follow the development of myositis by weeks to years. Cases lacking muscle involvement (i.e., dermatomyositis sine myositis) have also been reported. The most common manifestation is a purple-red discoloration of the upper eyelids, sometimes associated with scaling ("heliotrope" erythema; Fig. 54-3) and periorbital edema. Erythema on the cheeks and nose in a "butterfly" distribution may resemble the malar eruption of SLE. Erythematous or violaceous scaling patches are common on the upper anterior chest; posterior neck; scalp; and the extensor surfaces of the arms, legs, and hands. Erythema and scaling may be particularly prominent over the elbows, knees, and the dorsal interphalangeal joints. Approximately one-third of patients have violaceous, flat-topped papules over the dorsal interphalangeal joints that are pathognomonic of dermatomyositis (Gottron's sign or Gottron's papules; Fig. 54-4). These lesions can be contrasted with the erythema and scaling on the dorsum of the fingers that spares the skin over the interphalangeal joints of some SLE patients. Periungual telangiectasia may be prominent. Lacy or reticulated erythema may be associated with fine scaling on the extensor surfaces of the thighs and upper arms. Other patients, particularly those with long-standing disease, develop areas of hypopigmentation, hyperpigmentation, mild atrophy, and telangiectasia known as poikiloderma. Poikiloderma is rare in both SLE and scleroderma and, thus, can serve as a clinical sign that distinguishes dermatomyositis from these two diseases. Cutaneous changes may be similar in scleroderma and dermatomyositis and may include thickening and binding down of the skin of the hands (sclerodactyly) as well as Raynaud's phenomenon. However, the presence of severe muscle disease, Gottron's papules, heliotrope erythema, and poikiloderma serve to distinguish patients with dermatomyositis. Skin biopsy of erythematous, scaling lesions of dermatomyositis may reveal only mild nonspecific inflammation but sometimes may show changes indistinguishable from those found in SLE, including epidermal atrophy, hydropic degeneration of basal keratinocytes, edema of the upper dermis, and a mild mononuclear cell infiltrate. Direct immunofluorescence microscopy of lesional skin is usually negative, although granular deposits of immunoglobulin(s) and complement in the epidermal basement membrane zone have been described in some patients. Treatment should be directed at the systemic disease. Topical glucocorticoids are sometimes useful; patients should avoid exposure to ultraviolet irradiation and aggressively use photoprotective measures including use of broad-spectrum sunscreens.
Dermatomyositis. Periorbital violaceous erythema characterizes the classic heliotrope rash. (Courtesy of James Krell, MD; with permission.)
Gottron's sign. Dermatomyositis often involves the hands as erythematous flat-topped papules over the knuckles (Gottron's sign). Periungual telangiectases are also evident.
The cutaneous manifestations of lupus erythematosus (LE) (Chap. 319) can be divided into acute, subacute, and chronic types. Acute cutaneous LE is characterized by erythema of the nose and malar eminences in a "butterfly" distribution (Fig. 54-5). The erythema is often sudden in onset, accompanied by edema and fine scale, and correlated with systemic involvement. Patients may have widespread involvement of the face as well as erythema and scaling of the extensor surfaces of the extremities and upper chest. These acute lesions, while sometimes evanescent, usually last for days and are often associated with exacerbations of systemic disease. Skin biopsy of acute lesions may show only a sparse dermal infiltrate of mononuclear cells and dermal edema. In some instances, cellular infiltrates around blood vessels and hair follicles are notable, as is hydropic degeneration of basal cells of the epidermis. Direct immunofluorescence microscopy of lesional skin frequently reveals deposits of immunoglobulin(s) and complement in the epidermal basement membrane zone. Treatment is aimed at control of systemic disease; photoprotection in this as well as in other forms of LE is very important.
A. Acute cutaneous lupus erythematosus showing prominent, scaly, malar erythema. Involvement of other sun-exposed sites is also common. B. Acute cutaneous LE on the upper chest demonstrating brightly erythematous and slightly edematous papules and plaques. (B, Courtesy of Robert Swerlick, MD; with permission.)
Subacutecutaneous lupus erythematosus (SCLE) is characterized by a widespread photosensitive, nonscarring eruption. Most of these patients have SLE in which renal and CNS involvement is mild or absent. SCLE may present as a papulosquamous eruption that resembles psoriasis or annular lesions that resemble those seen in erythema multiforme. In the papulosquamous form, discrete erythematous papules arise on the back, chest, shoulders, extensor surfaces of the arms, and the dorsum of the hands; lesions are uncommon on the face, flexor surfaces of the arms, and below the waist. These slightly scaling papules tend to merge into large plaques, some with a reticulate appearance. The annular form involves the same areas and presents with erythematous papules that evolve into oval, circular, or polycyclic lesions. The lesions of SCLE are more widespread but have less tendency for scarring than do lesions of discoid LE. Skin biopsy reveals a dense mononuclear cell infiltrate around hair follicles and blood vessels in the superficial dermis, combined with hydropic degeneration of basal cells in the epidermis. Direct immunofluorescence microscopy of lesional skin reveals deposits of immunoglobulin(s) in the epidermal basement membrane zone in about one-half of these cases. A particulate pattern of IgG deposition throughout the epidermis has been associated with SCLE. Most SCLE patients have anti-Ro autoantibodies. Local therapy alone is usually unsuccessful. Most patients require treatment with aminoquinoline antimalarials. Low-dose therapy with oral glucocorticoids is sometimes necessary. Photoprotective measures against both ultraviolet B and A wavelengths are very important.
Discoid lupus erythematosus (DLE, also called chronic cutaneous LE) is characterized by discrete lesions, most often found on the face, scalp, and/or external ears. The lesions are erythematous papules or plaques with a thick, adherent scale that occludes hair follicles (follicular plugging). When the scale is removed, its underside shows small excrescences that correlate with the openings of hair follicles (so-called "carpet tacking"), a finding relatively specific for DLE. Long-standing lesions develop central atrophy, scarring, and hypopigmentation but frequently have erythematous, sometimes raised borders (Fig. 54-6). These lesions persist for years and tend to expand slowly. Only 5–10% of patients with DLE meet the American Rheumatism Association criteria for SLE. However, typical discoid lesions are frequently seen in patients with SLE. Biopsy of DLE lesions shows hyperkeratosis, follicular plugging, atrophy of the epidermis, hydropic degeneration of basal keratinocytes, and a mononuclear cell infiltrate adjacent to epidermal, adnexal, and microvascular basement membranes. Direct immunofluorescence microscopy demonstrates immunoglobulin(s) and complement deposits at the basement membrane zone in ~90% of cases. Treatment is focused on control of local cutaneous disease and consists mainly of photoprotection and topical or intralesional glucocorticoids. If local therapy is ineffective, use of aminoquinoline antimalarials may be indicated.
Discoid lupus erythematosus. Violaceous, hyperpigmented, atrophic plaques, often with evidence of follicular plugging, which may result in scarring, are characteristic of discoid lupus erythematosus (also called chronic cutaneous lupus erythematosus).
The skin changes of scleroderma (Chap. 323) usually begin on the hands, feet, and face, with episodes of recurrent nonpitting edema. Sclerosis of the skin begins distally on the fingers (sclerodactyly) and spreads proximally, usually accompanied by resorption of bone of the fingertips, which may have punched out ulcers, stellate scars, or areas of hemorrhage (Fig. 54-7). The fingers may actually shrink in size and become sausage-shaped, and because the fingernails are usually unaffected, the nails may curve over the end of the fingertips. Periungual telangiectases are usually present, but periungual erythema is rare. In advanced cases, the extremities show contractures and calcinosis cutis. Facial involvement includes a smooth, unwrinkled brow, taut skin over the nose, shrinkage of tissue around the mouth, and perioral radial furrowing (Fig. 54-8). Matlike telangiectases are often present, particularly on the face and hands. Involved skin feels indurated, smooth, and bound to underlying structures; hyper- and hypopigmentation are also often present. Raynaud's phenomenon (i.e., cold-induced blanching, cyanosis, and reactive hyperemia) is present in almost all patients and can precede development of scleroderma by many years. Linear scleroderma is a limited form of disease that presents in a linear, bandlike distribution and tends to involve deep as well as superficial layers of skin. The combination of calcinosis cutis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia has been termed the CREST syndrome. Anticentromere antibodies have been reported in a very high percentage of patients with the CREST syndrome but in only a small minority of patients with scleroderma. Skin biopsy reveals thickening of the dermis and homogenization of collagen bundles. Direct immunofluorescence microscopy of lesional skin is usually negative.
Scleroderma showing acral sclerosis and focal digital ulcers.
Scleroderma often eventuates in development of an expressionless, masklike facies.
Morphea is characterized by localized thickening and sclerosis of skin; it dominates on the trunk. This disorder may affect children or adults. Morphea begins as erythematous or flesh-colored plaques that become sclerotic, develop central hypopigmentation, and demonstrate an erythematous border. In most cases, patients have one or a few lesions, and the disease is termed localized morphea. In some patients, widespread cutaneous lesions may occur without systemic involvement. This form is called generalized morphea. Many adults with generalized morphea have concomitant rheumatic or other autoimmune disorders. Skin biopsy of morphea is indistinguishable from that of scleroderma. Scleroderma and morphea are usually quite resistant to therapy. For this reason, physical therapy to prevent joint contractures and to maintain function is employed and is often helpful. Treatment options for early, rapidly progressive disease include phototherapy (UVA1 or PUVA) or methotrexate 15–20 mg per week alone or in combination with daily glucocorticoids.
Diffuse fasciitis with eosinophilia is a clinical entity that can sometimes be confused with scleroderma. There is usually the sudden onset of swelling, induration, and erythema of the extremities frequently following significant physical exertion. The proximal portions of extremities (arms, forearms, thighs, legs) are more often involved than are the hands and feet. While the skin is indurated, it is usually not bound down as in scleroderma; contractures may occur early secondary to fascial involvement. The latter may also cause muscle groups to be separated and veins to appear depressed (i.e., the "groove sign"). These skin findings are accompanied by peripheral blood eosinophilia, increased erythrocyte sedimentation rate, and sometimes hypergammaglobulinemia. Deep biopsy of affected areas of skin reveals inflammation and thickening of the deep fascia overlying muscle. An inflammatory infiltrate composed of eosinophils and mononuclear cells is usually found. Patients with eosinophilic fasciitis appear to be at increased risk to develop bone marrow failure or other hematologic abnormalities. While the ultimate course of eosinophilic fasciitis is uncertain, many patients respond favorably to treatment with prednisone in doses ranging from 40–60 mg/d.
The eosinophilia-myalgia syndrome, a disorder reported in epidemic numbers in 1989 and linked to ingestion of l-tryptophan manufactured by a single company in Japan, is a multisystem disorder characterized by debilitating myalgias and absolute eosinophilia in association with varying combinations of arthralgias, pulmonary symptoms, and peripheral edema. In a later phase (3–6 months after initial symptoms), these patients often develop localized sclerodermatous skin changes, weight loss, and/or neuropathy (Chap. 323). The precise cause of this syndrome, which may resemble other sclerotic skin conditions, is unknown. However, the implicated lots of l-tryptophan contained the contaminant 1,1-ethylidene bis[tryptophan]. This contaminant may be pathogenic or a marker for another substance that provokes the disorder.